b88a980482
Motivation: Circular assignment of arenas to thread caches can lead to less than optimal mappings in cases where threads are (frequently) shutdown and started. Example Scenario: There are a total of 2 arenas. The first two threads performing an allocation would lead to the following mapping: Thread 0 -> Arena 0 Thread 1 -> Arena 1 Now, assume Thread 1 is shut down and another Thread 2 is started. The current circular assignment algorithm would lead to the following mapping: Thread 0 -> Arena 0 Thread 2 -> Arena 0 Ideally, we want Thread 2 to use Arena 1 though. Presumably, this is not much of an issue for most Netty applications that do all the allocations inside the eventloop, as eventloop threads are seldomly shut down and restarted. However, applications that only use the netty-buffer package or implement their own threading model outside the eventloop might suffer from increased contention. For example, gRPC Java when using the blocking stub performs some allocations outside the eventloop and within its own thread pool that is dynamically sized depending on system load. Modifications: Implement a linear scan algorithm that assigns a new thread cache to the arena that currently backs the fewest thread caches. Result: Closer to ideal mappings between thread caches and arenas. In order to always get an ideal mapping, we would have to re-balance the mapping whenever a thread dies. However, that's difficult because of deallocation.
Netty Project
Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients.
Links
How to build
For the detailed information about building and developing Netty, please visit the developer guide. This page only gives very basic information.
You require the following to build Netty:
- Latest stable Oracle JDK 7
- Latest stable Apache Maven
- If you are on Linux, you need additional development packages installed on your system, because you'll build the native transport.
Note that this is build-time requirement. JDK 5 (for 3.x) or 6 (for 4.0+) is enough to run your Netty-based application.
Branches to look
Development of all versions takes place in each branch whose name is identical to <majorVersion>.<minorVersion>. For example, the development of 3.9 and 4.0 resides in the branch '3.9' and the branch '4.0' respectively.